v4.2.1_CE_BP2_HF1

版本发布时间: 2023-12-18 22:03:26

oceanbase/oceanbase最新发布版本:v4.2.4_CE(2024-07-15 09:44:43)

Version information

This version addressed several customer and internal testing issues to enhance product stability.
Starting from V4.2.1_CE_BP2_HF1, batch rescan is disabled by default for the NESTED-LOOP JOIN (NLJ) and SUBPLAN FILTER (SPF) operators during cluster creation. However, for clusters upgraded from earlier versions to this version, batch rescan is enabled by default. If stability issues are found in batch rescan for the NLJ or SPF operator in an environment with large amounts data, you can disable batch rescan for the operator in the entire cluster by executing the SET GLOBAL _nlj_batching_enabled = false; statement. If the performance is not as expected after batch rescan is disabled, you can evaluate whether to enable batch rescan again based on the actual situation.

解决客户及内部测试遇到的问题，提升版本稳定性。
从V4.2.1_CE_BP2_HF1 版本开始，新建集群时，Nested Loop join（NLJ）和 SUBPLAN FILTER（SPF）算子的 BATCH RESCAN 优化默认会被关闭。然而，对于从老版本升级上来的集群，它们会默认保持原来的 BATCH RESCAN 打开的状态。对于存量的环境，如果发现 NLJ/SPF BATCH RESCAN 的稳定性问题，可以通过执行 SET GLOBAL _nlj_batching_enabled = false; 命令来关闭该优化，这将在整个集群范围内禁用 NLJ/SPF 的 BATCH RESCAN 优化。如果在关闭优化后性能不符合预期，可以根据具体情况重新评估并选择是否重新开启。